Elevator installations are used for transporting passengers and loads between floors of a building. Different elevator systems are known for that purpose. Traction elevators usually comprise an elevator car and a counterweight, which are connected by way of support means, wherein the support means is guided by way of a drive unit. In that case the drive unit drives the support means by way of a drive pulley and thereby moves the car and the counterweight in the building upwardly and downwardly in mutually opposite travel directions. Two cars can also be used instead of a car and a counterweight. In general, these two travel bodies are moved relative to one another by the support means.
Various arrangements of support means in elevator installations are known. In part, the two travel bodies are arranged directly in a so-called 1:1 suspension. The two ends of the support means are each then fixedly connected with a respective travel body and the support means is guided by way of the drive pulley. The circumferential speed of the drive pulley, the speed of the support means and the speed of the travel bodies are identical. In the case of a so-called 2:1 suspension, the support means is fastened in the building and the travel bodies are suspended at the support means by way of support rollers. The circumferential speed of the drive pulley and the speed of the support means at the drive pulley are thus twice as high as the speed of the travel bodies. In the case of 4:1 suspension, the support means is fastened in the building and the travel bodies are suspended at the support means by way of support rollers with double hanging, wherein the support means is also appropriately guided in the building again by way of a roller. The circumferential speed of the drive pulley and the speed of the support means at the drive pulley are thus four times as high as the speed of the travel bodies. Thus, by way of the form of suspension, on the one hand the supporting force in the support means and a required drive moment at the drive pulley are reduced in correspondence with the selected suspension and the circumferential speed of the drive pulley is correspondingly increased.
An elevator installation with a 4:1 suspension is known from WO 2012/115632, wherein support means in the form of support belts are used and the associated rollers for deflection of the support belt are arranged in space-saving manner in the shaft. Equally, an elevator installation is known from WO 2006/005215, in which the required shaft rollers are arranged to be fanned out for preserving the support belt.
It is disadvantageous with the illustrated elevator installations that on the one hand the support belts are twisted between the rollers and in part exposed to additional diagonal tension due to rollers arranged to be laterally offset.